RL10 engine – pushing towards 60 years of service – to live on with Vulcan

Aerojet Rocketdyne’s RL10 engine is continuing to beat out its younger competitors, winning another future role as the upper stage engine for the United Launch Alliance (ULA) Vulcan/Centaur rocket. The engine is no strange to ULA, providing a key role with both of its Delta IV and Atlas V rockets that Vulcan will eventually replace.
The RL10 – which is used in various forms with Atlas’ Centaur Upper Stage (RL10A-3) and Delta IV’s Upper Stage (RL10B-2)- has a history back to the Saturn I’s S-IV Stage.

It was first tested on the ground in 1959 and debuted on a launch in 1962 in the dual engine RL10A-3 configuration.

Due to an underperformance of the Atlas V booster, Centaur’s single burn duration of thirteen minutes and 38 seconds was extended to overcome the shortfall. Centaur ably delivered Cygnus into the correct 230km orbit and into its correct RAAN (Right Ascension of the Ascending Node), which ultimately classed the mission as a success.

The NGE effort was tested on a demonstrator rig called the “RLXX”. Notably, the RL10 that will power the Centaur on the Vulcan will evolve to the RL10C-X.

“ULA and Aerojet Rocketdyne have a long and successful history together that began with the first flight of our Atlas and Delta rockets in the 1960s,” said Tory Bruno, ULA president and CEO. “We could not be more pleased to have selected the proven and reliable RL10 to power our Vulcan Centaur upper stage.”

ULA announced the strategic partnership for the RL10 upper stage following a competitive procurement process.

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This partnership is a long-term agreement for Aerojet Rocketdyne to provide upper stage propulsion for the next decade. As part of this partnership, Aerojet Rocketdyne will provide RL10s and develop the RL10C-X, the next generation of the RL10 family.

The RL10C-X will increase the use of additive manufacturing and introduce other advanced technologies to improve the quality, reliability, affordability and performance.

Last year, Aerojet Rocketdyne successfully hot-fire tested a full-scale, additively manufactured thrust chamber assembly for the RL10 that was built from a copper alloy using a 3-D printing technique known as selective laser melting or SLM. Since then, the company has been working to develop and qualify a variety of components that take advantage of SLM technology.

RL10 Hot Fire – via Aerojet Rocketdyne

While some terms of the agreement remain confidential, it includes a long-term commitment by ULA to use RL10 engines on the company’s current Centaur and next-generation Centaur upper stages for future ULA procurements, as well as a joint commitment to invest in next-generation engine development.

“The agreement also defines a path forward that will enable us to develop the next generation of RL10 engines that will incorporate additive manufacturing and other advanced technologies to make the engine more affordable while retaining its proven performance and reliability,” noted Aerojet Rocketdyne CEO and President Eileen Drake.

“With nearly 500 engines flown in space over the last five decades, the RL10 has earned an unmatched reputation in the industry. We will continue to build this proud legacy by supporting ULA’s new Vulcan Centaur rocket for many years to come.”